Thisstory was updated at 3:23 p.m. EDT.
Theoff-target landing of a Russian Soyuz spacecraft during its return to Earth onSaturday posed a serious risk to the three astronauts aboard, Russian spaceofficials and reports suggest.
An apparentmalfunction in a mechanism designed to jettison the Soyuz TMA-11 spacecraft?spropulsion module from its crew-carrying descent capsule threatened the livesof the three astronauts aboard, Russia?s Interfax News Agency reportedTuesday.
The Soyuz landedon Saturday about 260 miles (420 km) short of its intended target in thearid central Asian steppes of Kazakhstan returning to Earth under a backup,ballistic reentry path.
NASA spaceoperations chief Bill Gerstenmaier said that while an investigation is stillunder way, the most likely cause of the atypical landing is a faulty cable,which may have had an electrical short that commanded the ballistic descent. TheSoyuz astronauts also reported experienced unusual shaking and buffeting duringreentry, suggesting a module separation malfunction as well, Gerstenmaier said.?
?TheRussians immediately set up a commission,? Gerstenmaier said. ?They?re going togo off and investigate this, they?ll get the capsule back and they?llunderstand the data.?
Thesteeper-than-usual landing subjected Soyuz cosmonaut commander YuriMalenchenko, returning U.S. astronaut - and Expedition 16 commander - PeggyWhitson and South Korea?s first spaceflyer So-yeon Yi to higher than normalgravitational loads that peaked at about 8-Gs for about one minute,Gerstenmaier said.
Yi describedthe descent as frightening in a post-landing press conference in Russia.
"Atfirst I was really scared because it looked really, really hot and I thought wecould burn,'' she said, according to the Associated Press, adding thatlater she noticed that it wasn?t even warm inside the Soyuz. "I looked atthe others and I pretended to be OK.''
Russia?sthree-segment Soyuz spacecraft are made up of an engine-carrying propulsionmodule, central crew capsule with a bottom-mounted heat shield and an orbitalmodule. The orbital and propulsion modules are designed to be discarded duringreentry, leaving the bell-shaped crew capsule to land under parachutes andretrorockets on the Kazakh steppe.
Citing anunmanned space official close to Russia?s post-landing investigation, Interfaxreported that the propulsion module did not jettison properly, preventing theSoyuz?s heat shield from bearing the brunt of the fiery temperatures duringreentry.
Instead,the spacecraft?s hatch side was facing forward and suffered some heat damagebefore the propulsion module separated for good and allowed a successfullanding, the news agency reported.
"It isa great success that the crew are safe and sound. The whole thing could haveended much worse. You can say that the situation was on the edge of arazor," Interfax quoted its source as saying.
Saturday?slanding marked the second consecutive Soyuz landing to return to Earth on aballistic trajectory, falling like a cannonball until the parachutes open.
Expedition15 cosmonauts and a Malaysian astronaut also experienceda ballistic reentry during their Oct. 21, 2007 landing, as did thecrew of Expedition 6 - which included U.S. astronaut Don Pettit - in May 2003. The2007 event also included a module separation malfunction early in the reentryprocess , Gerstenmaier said.
?You?realways concerned about the crew on any reentry vehicle,? NASA space station programmanager Mike Suffredini said in a post-landing interview on NASA TV. ?We had afew minutes there where we weren?t sure whether they had a ballistic landing,or something else.?
Russia hashad additional experience with Soyuz module separation problems in the past. InJanuary 1969, a returning Soyuz 5 spacecraft with Soviet cosmonaut BorisVolynov failed to separate immediately from its crew capsule. It eventuallypulled free to allow Volynov?s Soyuz to perform a ballistic reentry and make arough landing, according to the European spaceflight site EncylopediaAstronautica.
Russia?sInterfax News Agency and the Associated Press contributed to this report.
- VIDEO: ISS Commander Peggy Whitson Takes Charge
- NEW IMAGES: NASA's STS-123 Shuttle Mission in Pictures
- VIDEO: Europe's First ISS Cargo Ship Arrives